BUCHAREST (AFP).- Romanian investigators have not found seven masterpieces that were stolen from a Dutch museum last year, despite extensive searches at several locations after the arrest of three suspected thieves, a source close to the probe said Thursday.

Three Romanians allegedly involved in the spectacular theft of the paintings, including works by Picasso, Monet, Matisse and Gauguin, from the Kunsthal in Rotterdam in October were arrested overnight Monday in Bucharest.

"During the investigation we have searched several locations," the source said.

"But police are still looking for the paintings, which may have transited through Romania," the source added.

The three men had been living in the Netherlands for several years and were known as underworld members.

"There are indications that several other persons were involved in the theft," Romania's police chief Petre Toba said Thursday.

A day earlier, Romanian daily Evenimentul Zilei reported the suspects were caught while trying to sell the art works.

The Bucharest court that charged the suspects said they were accused of "setting up a criminal ring and complicity to aggravated theft," and remanded for 29 days.

Two Dutch investigators and a prosecutor arrived in Romania on Thursday for talks with the judiciary regarding the three arrests.

Experts said the paintings were worth between 50 million and 200 million euros ($66 million and $266 million) on the open market at the time of the theft, the biggest such heist in 20 years.

The spectacular theft gripped the Netherlands and the art world as police apparently struggled to piece the crime together, despite putting 25 officers on the case.

Dutch police released grainy security camera footage of the theft, which took place around 3:00 am. The footage showed two apparently young men entering and leaving the museum within barely 90 seconds.